| 摘要 |
PURPOSE:To make it possible to introduce impurities into a microscopic region having no defects by a method wherein, after a polycrystalline silicon thin film has been selectively irradiated with a focussed ion, a substrate is heated up, or the ion beam is selectively projected thereon simultaneously with the heating of the substrate. CONSTITUTION:A polycrystalline silicon film 2 is deposited by projecting an impurity ion beam 1 thereon. Then, an accelerated diffusion impurity layer 6 is formed on a substrate 3 by scanningly projecting the focussed ion beam 4 of the desired impurity ions while the part directly above the substrate region, on which impurities are introduced, is being heated up to the temperature at which accelerated diffusion is generated. As the distance of heat diffusion at the above-mentioned temperature is short, the impurities of the non-irradiation section remain in the thermal diffusion impurity layer 5 of the polycrystalline silicon film 2, no infiltration of impurities into the substrate 3 occurs, and the impurities are introduced of impurities into the desired region only. As a result, the impurity introduction layer of low crystal defect density can be formed.
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